Many computer guided orthopaedic surgical procedures are based on determining the position of bones, and relating this position into the computer via some type of ultrasonic, magnetic resonance, or optical sensor. A similar sensor is attached or contained within the surgical instrument and subsequently guided via a computer into the desired position within the patient. U.S. Patents and patent Publications relating to computer guided surgery include U.S. Pat. No. 5,520,694 and U.S. Patent Application Publication Nos. 2003/0153978 A1 and 2003/01538829 A1, each of which is hereby incorporated by reference. Similar computer guided navigation systems are disclosed in U.S. Pat. Nos. 6,514,259; 6,434,507; 6,428,547; 6,424,856; 6,351,659; 6,223,067; 6,187,018; 6,178,345; 5,889,834; 5,769,861; 5,702,406; 5,643,268; and 5,628,315, along with U.S. Patent Application Publication No. 2002/0038118 A1, each of which is hereby incorporated by reference. The accuracy of this guidance is dependent on various factors including, for example, computer hardware and software resolution, the location of the sensor on the surgical instrument, and manufacturing tolerances of the sensor and its attachment mechanism to the surgical instrument.
Tight manufacturing tolerances often result with increased cost of the attachment mechanism and require precise alignment of the components before assembly. This may decrease the user-friendliness of the operation of the attachment mechanism. In an operating room environment, for example, and particularly with the advent of minimally invasive surgery, the maneuvering space available to the surgeon becomes increasingly smaller. Precise alignment of tightly machined components having small tolerances may be difficult.